Obesity and diabetes are serious health problems in the United States, with rapidly increasing prevalence and incidence over the last 10 years. National data document alarming increases in overweight and obesity, and among Latinos the prevalence is 78%, markedly higher than in the general population. An estimated 25.6 million people 20 years or older have diabetes in the U.S., with the greatest increases in prevalence among racial and ethnic minority populations, further complicated by disparities in socioeconomic status. Hispanics face a diabetes prevalence twice that of non-Hispanic whites and suffer higher rates of diabetes complications and mortality. Nationally, it is estimated that there are over 2.6 million hired farm workers in the U.S., and California is among the largest employers of these workers. In California, over 450,000 people are employed in agriculture, with more than two-thirds being of Latino ethnicity. Most are immigrants with low levels of education and many have Spanish as their only language. This population also faces issues with limited access to health care, compounded by poverty and low socioeconomic status. While intervention efforts have demonstrated that an intensive lifestyle approach promoting diet and physical activity can significantly reduce obesity and diabetes incidence, there continues to be a need for effective programs designed for underserved and immigrant populations - a sizeable proportion of the U.S. working population. The overall goal of this study is to validate the effectiveness of an obesity and diabetes intervention among low-literate immigrant farm workers. We propose that a lifestyle intervention delivered at the agricultural worksite will improve obesity and diabetes risk for employees and will prove to be cost effective for the employer. The collaboration of established investigators at UC Davis with Reiter Affiliated Companies (RAC, a large berry grower in California) and the Health Initiative of the Americas at UC Berkeley (experts in organizing health campaigns for underserved immigrant populations) creates a unique opportunity to achieve significant positive health outcomes through a total worker health approach. Our efforts will build upon two successful pilot studies conducted with RAC and will enable us to reach a larger number of people and evaluate the program's translation and sustainability potential. Successful achievement of the project goals will enable dissemination of the program to improve the health of workers via a cost effective and culturally-tailored obesity and diabetes risk factor intervention.